2 points
Time management is very much important in IIT JAM. The eduncle test series for IIT JAM Mathematical Statistics helped me a lot in this portion. I am very thankful to the test series I bought from eduncle.
Nilanjan Bhowmick AIR 3, CSIR NET (Earth Science)
- CSIR NET
- Life Sciences
An enzyme requires aspartate and histidine residues in the catalytic site to be deprotonated for activity. assuming that pka of side chains of both the residues
An enZyme requires aspartate and histidine residues in the catalytic site to be deprotonated for activity. Assuming that pKa of side chains of both the residues are 4.4 and 6.5 respectively, and the enzyme is found to be 90% active at a pH of7.5 how much would be the expected enzyme activity at a pH of 6.52 A. 78% B. 70% C. 50% D. 25% 19. On addition of small amounts of a fatty acid to an aqueous solution, which of the 19 folloWing would occur: A. Formation of a monolayer at the air-water interface B. Formation of b1-layers at the air-water intertace C. Formation of micelles in the solution D. Formation of liposomes in the solution
0 Answer(s)
Answer Now
- 0 Likes
- 1 Comments
- 0 Shares
Do You Want Better RANK in Your Exam?
Start Your Preparations with Eduncle’s FREE Study Material
- Updated Syllabus, Paper Pattern & Full Exam Details
- Sample Theory of Most Important Topic
- Model Test Paper with Detailed Solutions
- Last 5 Years Question Papers & Answers
Sign Up to Download FREE Study Material Worth Rs. 500/-
Surendra kumar meghwal
Most Upvoted Answer An enzyme requires both aspartate (pKa of side chain = 4.5) and histid... Explanation: To understand why the expected enzyme activity is close to 10% at pH 5.5, we need to consider the pKa values of the aspartate and histidine residues in the catalytic site. At pH 5.5, both the aspartate and histidine residues will be partially protonated. The pKa of aspartate is 4.5, so at pH 5.5, the aspartate residue will be mostly protonated but some of it will be deprotonated. The pKa of histidine is 6.5, so at pH 5.5, the histidine residue will be mostly deprotonated but some of it will be protonated. The enzyme requires both the aspartate and histidine residues to be fully protonated for activity. Since both residues are only partially protonated at pH 5.5, the enzyme activity will be reduced. The degree of protonation of the aspartate and histidine residues can be calculated using the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]) where pH is the pH of the solution, pKa is the pKa of the acid, [A-] is the concentration of the deprotonated form of the acid, and [HA] is the concentration of the protonated form of the acid. Using this equation, we can calculate the degree of protonation of the aspartate and histidine residues at pH 5.5: For aspartate: pH = 4.5 + log([A-]/[HA]) 5.5 = 4.5 + log([A-]/[HA]) log([A-]/[HA]) = 1 [A-]/[HA] = 10 This means that at pH 5.5, there will be 10 times more deprotonated aspartate than protonated aspartate. For histidine: pH = 6.5 + log([A-]/[HA]) 5.5 = 6.5 + log([A-]/[HA]) log([A-]/[HA]) = -1 [A-]/[HA] = 0.1 This means that at pH 5.5, there will be 10 times more protonated histidine than deprotonated histidine. Since both the aspartate and histidine residues need to be fully protonated for enzyme activity, the enzyme activity will be reduced when both residues are only partially protonated. Therefore, the expected enzyme activity at pH 5.5 will be close to 10%.